function [lam,x] = invpowerit(A,x,s,numsteps, ans)
As = A-s*eye(size(A));
for j = 1:numsteps
	y = As\x;
	[m,r] = max(abs(y));
	x = y/y(r);
	z(j) = 1/y(r)+s - ans;
end
for j = 1:numsteps-1
	z(j+1)/z(j)
end
lam = 1/y(r)+s